Portion of a display panel with a graphical user interface



FIG. 1 is a front view of a portion of a display panel with a graphical user interface, showing a first embodiment; and,

FIG. 2 is a front view of a portion of a display panel with a graphical user interface, showing a second embodiment.

The broken lines in the display panel illustrate graphical features that form no part of the claimed design. 

CLAIM The ornamental design for a portion of a display panel with a graphical user interface, substantially as shown and described. 